July.15, 2002 1

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

1

WIRE-LAN TESTING OF WIRELESSNETWORK-CENTRIC SYSTEMS

July.15, 2002 2

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

July.15, 2002 2

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

July.15, 2002 3

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

NETWORK-CENTRIC SYSTEMS

Command and Control

Police, Fireman and Ambulance

Air Traffic Control

Distributed Sensor Fusion

Mobile Agents

Network Adaptation

Layer 3 of Ad Hoc Networks“Effects of Wireless Physical Layer Modeling in Wireless Ad Hoc Networks”Takai, Martin, Bagrodia, MobiCom 2001.

July.15, 2002 4

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

CONCEPT

July.15, 2002 5

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

EMULATE DIGITAL RADIO TRANSMISSION

Station 1 Station 2

Wire Transmission(s)

Data/ Voice/ Video Packet

probe

July.15, 2002 6

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

B

8 Nodes Within LOS 6 Cells => 6 Datapoints (Multipath)

Mountain

SIMULATE RADIO PROPAGATION (TRANSMIT)

This NodeB

July.15, 2002 7

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

802.11 DCF EMULATION

July.15, 2002 8

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

SEGMENT FRAMES, EMULATE RADIO TRANSMIT SPEED

Data/ Voice/ Video Packet, Analog Xmssn

ProbeTrailer

Interframe gap computed to have last bit of the trailercoincide with the last bit of the emulated packet.

Where data is unimportant, e.g. background traffic, can send minimum-sized trailer to save bandwidth.

Other emissions (jamming, co-site, infared, optical)

Start/ChangeStop/Change

non-realtime simulation

EMULATION TYPE

1:

2:

3:

4:

July.15, 2002 9

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

SIMULATE COLLISIONS R

ea

l Tim

e

Transmit Part I

Receive Part I

Detect Collision

Transmit Part I

Receive Part I

Receive Part II Transmit Part II

Detect Collision

Station I Station II

ONLY ONE STATION COMPLETELY SENDS RADIO FRAME

July.15, 2002 10

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

CONSISTENT, DISTRIBUTED EMULATION

RANDOM SEED

probe

For multiple active probes, consistency rule guarantees all receivers choose the same random seed.

July.15, 2002 11

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

RANDOM SEED BRINGS FAIRNESS BACK TO COLLISION MODEL

ProbeTrailer Receiver Timeline

Time Of First Received Bit.

Random Seed Sets Virtual Receive TimeWithin These Limits.

July.15, 2002 12

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

DEMONSTRATION

July.15, 2002 13

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

13

WIRELESS NETWORK SIMULATION:

DEMONSTRATION LAN

10 Base T

Linux 2.2.15

Uses Ordinary PC Components + Software + Modified Driver For 3 Com Ethernet III Card

i586 i586 i586 i686

i686 i686 i686

Two Drops Required For Identical Receive Ordering

July.15, 2002 14

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

APPROXIMATE WIRELESS LAN THROUGHPUT

July.15, 2002 15

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

SATURATION THROUGHPUT

550

600

650

700

750

800

850

610623

721714

812812

906912

10321026

Offered Traffic, Kbit/s

Thr

ough

put,

Kbi

t/s

Tests, Five PCs

Bianchi, Five Stations

Tests, Seven PCs

Bianchi, Seven Stations

Five PCsSeven PCs

Emulation ParametersData Length 1024 octetsMAC header 34 octetsChannel Bit Rate 1 Mbit/sSIFS 28 sSlot Time 50 sACK length 30 octetsPHY header 16 octetsPropagation delay 1 sDIFS 130 s

10 9.810 9.8max, avg frames delivered (1,000)

Five PCsSeven PCs

10 9.810 9.8

10 9.55.3 4.9

6.7 6.58.6 7.6

10 9.310 8.7

1.23 1.221.3 1.27max avg

1.23 1.231.32 1.31

1.25 1.241.31 1.30

Five PCsSeven PCs

Average Number Attempts Per Frame (Bianchi - 1.22, five stations)

July.15, 2002 16

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

1.23 1.221.3 1.27max avg

1.23 1.231.32 1.31

1.25 1.241.31 1.30

Five PCsSeven PCs

Bianchi - 1.22, five stations

AVERAGE ATTEMPTS PER FRAME

812812

906912

10321026

Offered Traffic(Kbit/s)

July.15, 2002 17

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

VARY CONTENTION WINDOW (SATURATION)

July.15, 2002 18

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

EXISTING APPROACHES

July.15, 2002 19

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

PACKET KILLER (CMU MONARCH PROJECT, …)

Receiver Filters MAC Source Address From List of Prohibited Addresses

Trace File (List Of Prohibited Addresses) Created Beforehand

Trace File Based On External Simulation/Experimentation Measurements

Some Practitioners Say Ethernet Good Enough To Represent Radio’s Collision-Based MACHOWEVER: Measured saturation throughput for 2 to 24 stations on

Ethernet exceeds 95 % utilization for 1024 octet packets. (Boggs, Mogul, Kent, ACM SIGCOMM ‘88). Bianchi demonstrates 80% saturation throughput for CSMA/CA with 5 stations.

July.15, 2002 20

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

STORM Federation (HLA)

SimulateRadioPropagation

SimulateNodalPositions

SimulateNodalPositions

(1) (1)

Both Receiver and Propagation Receive Data Message (1).

SimulateRadioPropagation

SimulateNodalPositions

SimulateNodalPositions

Receiver’s Emulated Radio Holds Data Message (1). Until It Receives Release-Packet (2) From Propagator.

(1)

(2)

Propagator

July.15, 2002 21

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

DIS Transmission Characteristic Packet

Transmission Characteristics Packet (1) Sent Prior to Data Packet (2).

Receiver Computes and Adjusts Timing and Reception Characteristics.

TADL Working Group Migrating DIS to HLA.

Other DIS Models:

Intercom

Electromagnetic Emission (Jamming), Designator (Cosite), Underwater Acoustic, IFF/ATC/NAVAIDS, Supplemental Emission/Entity State.

SimulateNodalPositions

SimulateNodalPositions

(1)(2)

July.15, 2002 22

WIRELESS NETWORK SIMULATION:

GENERAL DYNAMICSC4 Systems

COMPARISON (FOR REAL-TIME EMULATION)

Segmented Radio Frame (This Paper)

STORM (HLA)

Transmission-Characteristic

Frame (DIS/HLA)

Modifications To Tested System - + -

Congestion + - - Collision Model ++ - -

Large System Emulation - Wide-Area

Testing/Training -